Risk of breast cancer among users of aspirin and other anti-inflammatory drugs

Prophylactic aspirin intake and breast cancer risk; A systematic review and meta-analysis of observational cohort studies

Breast Cancer (BC) is the most common cancer amongst women. The chemo-preventative effects of aspirin on breast cancer have been demonstrated in several longitudinal studies however previous meta-analysis have shown inconsistent results. This study aimed to assess the relationship between aspirin use and BC risk, and to determine if there is a dose-response relationship between aspirin and BC risk. Studies incorporating BC risk with aspirin use published within the last twenty years were included. The study report is based on the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and Meta-Analysis of Observational Studies in Epidemiology. Twenty-eight cohort studies that reported BC incidence during a follow up of 4.4-32 years were included. Compared to non-users, aspirin users had a reduced risk of BC (HR = 0.91, c.i 0.81-0.97, p = 0.002). There was no obvious association between BC risk reduction and aspirin dose (HR = 0.94, c.i 0.85-1.04) or duration (HR = 0.86, c.i 0.71-1.03). Frequency, however, was associated with a reduced risk of BC (HR = 0.90, c.i 0.82-0.98). A risk reduction was observed in oestrogen receptor (ER) positive tumours (HR = 0.90, c.i 0.86-0.96, p = 0.0004) while no relationship was observed with ER negative tumours (HR = 0.94, c.i 0.85-1.05). This meta-analysis found an association between aspirin intake and BC risk reduction. A more favourable outcome was noted with ingestion of greater than 6 tablets of aspirin per week. Aspirin had a significant risk reduction in patients with ER positive tumours compared to ER negative BC.

Aspirin Use and Risk of Breast Cancer: A Meta-analysis of Observational Studies from 1989 to 2019

BACKGROUND

Some evidence shows that aspirin can reduce the morbidity and mortality of different cancers, including breast cancer. Aspirin has become a new focus of cancer prevention and treatment research at present, however, clinical studies found conflicting conclusions of its anticancer characteristics.

MATERIALS AND METHODS

A systematic literature search was performed in 8 electronic databases. The pooled relative risk (RR) with 95% confidence interval (CI) was calculated using the random effects model to estimate the effect of aspirin on breast cancer.

RESULTS

Forty-two published articles with 99,769 patients were identified. The meta-analysis showed a significant decrease in breast cancer risk with aspirin use (RR, 0.92; 95% CI, 0.89-0.96; I² = 72%). Aspirin use decreased the risk of hormone receptor-positive tumors (estrogen receptor [ER]-positive RR, 0.89; 95% CI, 0.82-0.97; I²=54%; progesterone receptor [PR]-positive RR, 0.86; 95% CI, 0.78-0.95; I²=32%; ER- and PR-positive RR, 0.92; 95% CI, 0.85-1.00; I²=45%) and reduced the risk of breast cancer in postmenopausal women (RR, 0.92; 95% CI, 0.86-0.98; I²=59%). Further analysis showed that for the in situ breast cancer, regular-dose and more than 3 years use of aspirin were associated with the reduced risk of breast cancer.

CONCLUSION

This meta-analysis suggested that aspirin may reduce the overall risk of breast cancer, reduce the risk of breast cancer in postmenopausal women, hormone receptor-positive tumors, and in situ breast cancer. Larger, multicenter clinical studies are needed to find the optimal dose range, frequency, and duration of the aspirin use to explore the best benefit-risk ratio.

Quantifying bias in epidemiologic studies evaluating the association between acetaminophen use and cancer

Many observational studies explore the association between acetaminophen and cancer, but known limitations such as vulnerability to channeling, protopathic bias, and uncontrolled confounding hamper the interpretability of results. To help understand the potential magnitude of bias, we identify key design choices in these observational studies and specify 10 study design variants that represent different combinations of these design choices. We evaluate these variants by applying them to 37 negative controls - outcome presumed not to be caused by acetaminophen - as well as 4 cancer outcomes in the Clinical Practice Research Datalink (CPRD) database. The estimated odds and hazards ratios for the negative controls show substantial bias in the evaluated design variants, with far fewer of the 95% confidence intervals containing 1 than the nominal 95% expected for negative controls. The effect-size estimates for the cancer outcomes are comparable to those observed for the negative controls. A comparison of exposed and unexposed reveals many differences at baseline for which most studies do not correct. We observe that the design choices made in many of the published observational studies can lead to substantial bias. Thus, caution in the interpretation of published studies of acetaminophen and cancer is recommended.

Promising Hybrids Derived from S-Allylcysteine and NSAIDs Fragments against Colorectal Cancer: Synthesis, In-vitro Evaluation, Drug-Likeness and In-silico ADME/tox Studies

We synthesized twelve hybrids, S-allyl Cysteine methyl, ethyl and propyl ester-based non-steroidal anti-inflammatory drugs and their structures were elucidated by spectroscopic analysis. The chemopreventive potential of all compounds was evaluated against SW480 human colon adenocarcinoma cells and the non-malignant CHO-K1 cell line. Among the tested compounds, hybrids 10b-c, 11b and 12b displayed the best anticancer activity with IC₅₀ values between 0.131-0.183 mM and selectivity indices higher than 1 after 48 h of treatment. Selectivity indices were comparable to those reported for the reference drug, 5-fluorouracil (SI > 1). The SAR analysis showed that compounds with two carbon atom alkylic chains displayed the best activity (10b, 11b and 12b). Modeling studies including drug-likeness, bioactivity score and ADME/tox studies using online tools like molinspiration and Osiris suggested that these designed hybrids have a good pharmacological profile and can be considered as promising scaffolds for further studies in the search for new therapeutic alternatives to treat colorectal cancer.

Use of nonsteroidal anti-inflammatory drugs and breast cancer risk in a prospective cohort of postmenopausal women

BACKGROUND

Although anti-inflammatory agents could theoretically have anticancer properties, results from cohort studies on nonsteroidal anti-inflammatory drugs (NSAIDs) and breast cancer (BC) risk are inconsistent.

METHODS

We investigated the association between NSAID use and BC incidence in the French E3N prospective cohort, which includes 98,995 women born between 1925 and 1950 and insured by a health insurance plan that covers mostly teachers. Self-reported information on lifestyle and medical history has been collected biennially by questionnaires and matched with data from a drug reimbursement database covering the period 2004-2014. Women who self-reported current NSAID use in the 2000 or 2002 questionnaires or with at least two reimbursements in any previous 3-month period were defined as exposed to NSAIDs. Multivariable Cox regression models were used to estimate hazard ratios (HRs) for the association of NSAID use with BC risk.

RESULTS

In the current analysis, 62,512 postmenopausal women were followed between 2004 and 2014 (9 years on average, starting at a mean age of 63 years; 2864 incident BC). In multivariable models, there was no statistically significant association between NSAID use and BC risk [HR = 1.00 (0.92-1.08), compared with non-exposed women]. The NSAID-BC associations did not differ by NSAID types, BC subtypes, risk factors, and comorbidities, nor by duration and dose of use. However, a statistically significant interaction was observed by proton pump inhibitor (PPI) drug use (Pinteraction = 0.01) whereby a decreased risk of BC with NSAID use was only observed among women who also used PPI before.

CONCLUSION

Only women who used NSAIDs after having used PPI had a lower risk of BC. This result is novel and requires replication in other studies.

Aspirin might reduce the incidence of breast cancer: An updated meta-analysis of 38 observational studies

BACKGROUND

Many epidemiologic studies were performed to clarify the protective effect of regular aspirin use on breast cancer risks, but the results remain inconsistent. Here, we conducted an updated meta-analysis of 38 studies to quantitatively assess the association of regular aspirin use with risk of breast cancer.

METHOD

We performed a bibliographic database search in PubMed, Embase, Web of Science, Cochrane library, Scopus, and Google Scholar from January 1939 to December 2019. Relative risk (RR) estimates were extracted from eligible case-control and cohort studies and pooled using a random effects model. Subgroup analysis was conducted based on study design, aspirin exposure assessment, hormone receptor status, menopausal status, cancer stage as well as aspirin use duration or frequency. Furthermore, sensitivity and publication bias analyses were performed.

RESULTS

Thirty eight studies of 1,926,742 participants involving 97,099 breast cancer cases contributed to this meta-analysis. Compared with nonusers, the aspirin users had a reduced risk of breast cancer (RR = 0.91, 95% confidence interval [CI]: 0.87-0.95, P value of significance [Psig] < .001) with heterogeneity (P value of heterogeneity [Phet] < .001, I = 82.6%). Subgroup analysis revealed a reduced risk in case-control studies (RR = 0.83, 95% CI: 0.78-0.89, Psig < .001), in hormone receptor positive tumors (RR = 0.91, 95% CI: 0.88-0.94, Psig < .001), in situ breast tumors (RR = 0.79, 95% CI: 0.71-0.88, Psig < .001), and in postmenopausal women (RR = 0.89, 95% CI: 0.83-0.96, Psig = .002). Furthermore, participants who use aspirin for >4 times/wk (RR = 0.88, 95% CI: 0.82-0.96, Psig = .003) or for >10 years (RR = 0.94, 95% CI: 0.89-0.99, Psig = .025) appeared to benefit more from the reduction in breast cancer caused by aspirin.

CONCLUSIONS

Our study suggested that aspirin use might be associated with a reduced risk of breast cancer, particularly for reducing the risk of hormone receptor positive tumors or in situ breast tumors, and the risk of breast cancer in postmenopausal women.

Low-dose aspirin use and risk of contralateral breast cancer: a Danish nationwide cohort study

Observational studies of aspirin use and breast cancer risk have provided inconsistent results. The occurrence of contralateral breast cancer (CBC) among breast cancer survivors may serve as a useful high-risk model to identify preventive drug effects. Using this model, we examined the association between post-diagnosis use of low-dose aspirin and risk of CBC. We identified all women recorded with a first primary breast cancer in the Danish Breast Cancer Cooperative Group Database between 1996 and 2012. Information on drug use, tumor and patient characteristics, treatment, and CBC was obtained from nationwide registries. In the main analysis, we defined time-varying post-diagnosis low-dose aspirin use as two or more prescriptions filled during follow-up and applied a one-year exposure lag. Cox proportional hazard regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between post-diagnosis low-dose aspirin use and CBC risk. Among 52,723 breast cancer patients, 1,444 women developed CBC during a median follow-up of 4.8 years. The adjusted HR for CBC associated with post-diagnosis use of low-dose aspirin was 0.91 (95% CI: 0.75-1.09). We observed no substantial variation in HRs according to pattern of low-dose aspirin use or estrogen receptor status of the first or the contralateral breast cancer. In conclusion, this large nationwide cohort study of breast cancer survivors does not provide strong evidence suggesting an association between post-diagnosis use of low-dose aspirin and risk of CBC.

Aspirin as a potential modality for the chemoprevention of breast cancer: A dose-response meta-analysis of cohort studies from 857,831 participants

BACKGROUND

Previous meta-analyses on the relationship between aspirin use and breast cancer risk have drawn inconsistent results. In addition, the threshold effect of different doses, frequencies and durations of aspirin use in preventing breast cancer have yet to be established.

RESULTS

The search yielded 13 prospective cohort studies (N=857,831 participants) that reported an average of 7.6 cases/1,000 person-years of breast cancer during a follow-up period of from 4.4 to 14 years. With a random effects model, a borderline significant inverse association was observed between overall aspirin use and breast cancer risk, with a summarized RR = 0.94 (P = 0.051, 95% CI 0.87-1.01). The linear regression model was a better fit for the dose-response relationship, which displayed a potential relationship between the frequency of aspirin use and breast cancer risk (RR = 0.97, 0.95 and 0.90 for 5, 10 and 20 times/week aspirin use, respectively). It was also a better fit for the duration of aspirin use and breast cancer risk (RR = 0.86, 0.73 and 0.54 for 5, 10 and 20 years of aspirin use).

METHODS

We searched MEDLINE, EMBASE and CENTRAL databases through early October 2016 for relevant prospective cohort studies of aspirin use and breast cancer risk. Meta-analysis of relative risks (RR) estimates associated with aspirin intake were presented by fixed or random effects models. The dose-response meta-analysis was performed by linear trend regression and restricted cubic spline regression.

CONCLUSION

Our study confirmed a dose-response relationship between aspirin use and breast cancer risk. For clinical prevention, long term (>5 years) consistent use (2-7 times/week) of aspirin appears to be more effective in achieving a protective effect against breast cancer.

Associations between aspirin use and the risk of cancers: a meta-analysis of observational studies

Background

Epidemiological studies have clarified the potential associations between regular aspirin use and cancers. However, it remains controversial on whether aspirin use decreases the risk of cancers risks. Therefore, we conducted an updated meta-analysis to assess the associations between aspirin use and cancers.

Methods

The PubMed, Embase, and Web of Science databases were systematically searched up to March 2017 to identify relevant studies. Relative risks (RRs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

A total of 218 studies with 309 reports were eligible for this meta-analysis. Aspirin use was associated with a significant decrease in the risk of overall cancer (RR = 0.89, 95% CI: 0.87–0.91), and gastric (RR = 0.75, 95% CI: 0.65–0.86), esophageal (RR = 0.75, 95% CI: 0.62–0.89), colorectal (RR = 0.79, 95% CI: 0.74–0.85), pancreatic (RR = 0.80, 95% CI: 0.68–0.93), ovarian (RR = 0.89, 95% CI: 0.83–0.95), endometrial (RR = 0.92, 95% CI: 0.85–0.99), breast (RR = 0.92, 95% CI: 0.88–0.96), and prostate (RR = 0.94, 95% CI: 0.90–0.99) cancers, as well as small intestine neuroendocrine tumors (RR = 0.17, 95% CI: 0.05–0.58).

Conclusions

These findings suggest that aspirin use is associated with a reduced risk of gastric, esophageal, colorectal, pancreatic, ovarian, endometrial, breast, and prostate cancers, and small intestine neuroendocrine tumors.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4156-5) contains supplementary material, which is available to authorized users.

Pre-diagnostic aspirin use and mortality after breast cancer

BACKGROUND

Whether aspirin or other nonsteroidal anti-inflammation drug (NSAID) use is associated with mortality following breast cancer remains unclear. Consideration of use patterns and interaction with obesity may help to clarify the inconsistent results.

METHODS

Pre-diagnosis NSAID use, weight, and height were assessed ~ 3 months after diagnosis through in-person interviews with a population-based cohort of 1,442 women with first primary breast cancer. Vital status was determined through the national death index after ~ 18 years of follow-up (N = 237/597 breast cancer-specific/all-cause deaths). We used Cox proportional hazards regression to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Multiplicative interaction by body mass index (BMI) was evaluated using the likelihood ratio test.

RESULTS

Ever aspirin use was inversely associated with breast cancer-specific mortality (HR 0.87, 95% CI 0.59-1.29), but positively associated with all-cause mortality (HR 1.21, 95% CI 0.99-1.48); the CIs included the null values. The HRs, however, were more pronounced for the highest level of duration, frequency, regularity, and timing for all-cause, but not breast cancer-specific mortality. Interactions with BMI revealed no significant heterogeneity (p_interaction = 0.37 and p_interaction = 0.36, respectively).

CONCLUSION

Pre-diagnosis aspirin use was not strongly associated with mortality following breast cancer. The all-cause mortality associations, however, were slightly stronger when we considered patterns of use.

Low-Dose Aspirin Reduces Breast Cancer Risk in Women with Diabetes: A Nationwide Retrospective Cohort Study in Taiwan

PURPOSE

Low-dose aspirin is commonly used for preventing cardiovascular disease in people with diabetes, but its association with cancer remains controversial. This study used a nationwide population-based reimbursement database to investigate the relationship between low-dose aspirin use and breast cancer incidence in women with diabetes.

METHODS

This retrospective cohort study was conducted using data retrieved from the National Health Insurance Research Database in Taiwan from January 1, 1998 to December 31, 2011. Women diagnosed as having diabetes with low-dose aspirin use (75-165 mg daily) were identified as the study population, whereas those without low-dose aspirin use were selected as the comparison group.

RESULTS

We analyzed 148,739 patients with diabetes. Their mean age (standard deviation) was 63.3 (12.8) years. A total of 27,378 patients were taking aspirin. Overall, the use of aspirin in patients with diabetes reduced the risk of breast cancer by 18% (hazard ratio [HR], 0.82; 95% confidence interval [CI], 0.71-0.94) after adjustment for potential confounders, namely age and comorbidities. Specifically, a cumulative dose of aspirin exceeding 88,900 mg was observed to reduce the risk of breast cancer by 47% (HR, 0.53, 95% CI, 0.43-0.67); however, low (<8,600 mg) and medium (8,600-88,900 mg) cumulative doses of aspirin did not reduce the risk of breast cancer.

CONCLUSIONS

Our findings suggest that a cumulative aspirin dosage of more than 88,900 mg daily was associated with a reduced risk of breast cancer in women with diabetes. However, additional studies are necessary to confirm these findings.

Regular and low-dose aspirin, other non-steroidal anti-inflammatory medications and prospective risk of HER2-defined breast cancer: the California Teachers Study

BACKGROUND

Regular users of aspirin may have reduced risk of breast cancer. Few studies have addressed whether risk reduction pertains to specific breast cancer subtypes defined jointly by hormone receptor (estrogen and progesterone receptor) and human epidermal growth factor receptor 2 (HER2) expression. This study assessed the prospective risk of breast cancer (overall and by subtype) according to use of aspirin and other non-steroidal anti-inflammatory medications (NSAIDs) in a cohort of female public school professionals in California.

METHODS

In 1995 - 1996, participants in the California Teachers Study completed a baseline questionnaire on family history of cancer and other conditions, use of NSAIDs, menstrual and reproductive history, self-reported weight and height, living environment, diet, alcohol use, and physical activity. In 2005-2006, 57,164 participants provided some updated information, including use of NSAIDs and 1457 of these participants developed invasive breast cancer before January 2013. Multivariable Cox proportional hazards regression models provided hazard rate ratios (HRR) for the association between NSAID use and risk of invasive breast cancer as well as hormone receptor- and HER2-defined subtypes.

RESULTS

Developing breast cancer was associated inversely with taking three or more tablets of low-dose aspirin per week (23% of participants). Among women reporting this exposure, the HRR was 0.84 (95% confidence interval (CI) 0.72-0.98) compared to those not taking NSAIDs and this was particularly evident in women with the hormone receptor-positive/HER2-negative subtype (HRR = 0.80, 95% CI 0.66-0.96). Use of three or more tablets of "other" NSAIDs was marginally associated with lower risk of breast cancer (HRR = 0.79, 95% CI 0.62-1.00). Other associations with NSAIDs were generally null.

CONCLUSION

Our observation of reduced risk of breast cancer, among participants who took three or more tablets of low-dose aspirin weekly, is consistent with other reports looking at aspirin without differentiation by dose. This is the first report to suggest that the reduction in risk occurs for low-dose aspirin and not for regular-dose aspirin and only among women with the hormone receptor-positive/HER2-negative subtype. This preliminary study builds on previous knowledge and further supports the need for formal cancer chemoprevention studies of low-dose aspirin.

Patterns of acute inflammatory symptoms prior to cancer diagnosis

Although many studies have examined the role of chronic inflammation in cancer development, few studies discuss the patterns of acute inflammation prior to cancer diagnosis. Patients with lung, colorectal, prostate, or breast cancer between 1 July 2006 and 31 December 2009 and their metastatic status at diagnosis were determined through the Swedish Cancer Register. Non-steroidal anti-inflammatory drugs (NSAIDs) use in the year prior to cancer diagnosis was assessed through the Swedish Prescribed Drug Register. There were 13,945 patients identified with breast cancer, 6501 with prostate cancer, 5508 with lung cancer, and 12,723 with colon cancer. For metastatic patients, there is strong evidence of higher NSAIDs use 1–3 months compared to 10–12 months prior to diagnosis (breast odds ratio (OR) = 3.54, 95% CI 2.26–5.54; prostate OR = 3.90, 95% CI 3.10–4.90; lung OR = 2.90 95% CI 2.44–3.44; colorectal OR = 1.67, 95% CI 1.36–2.05). For non-metastatic patients, increased NSAIDs use 1–3 months prior to diagnosis was also observed, but only to a smaller extent for lung and prostate cancer (prostate OR = 1.48, 95% CI 1.27–1.72; lung 1.41, 95% CI 1.19–1.67). In conclusion, if NSAIDs use reflects underlying inflammatory symptoms, there is support for the hypothesis that advanced cancer was associated with an acute inflammatory process.

Use of acetaminophen in relation to the occurrence of cancer: a review of epidemiologic studies

Acetaminophen has several pharmacologic properties that suggest it could be carcinogenic in human beings. A number of epidemiologic studies have been conducted to examine whether use of acetaminophen actually predisposes to the occurrence of one or more forms of cancer. There are inherent limitations to many of these studies, including the inaccurate identification of users and nonusers of acetaminophen, relatively short follow-up for cancer incidence, and the potential for confounding by indication. The present manuscript reviews the results of epidemiologic studies of acetaminophen use in relation to cancer incidence published through the end of 2015. The limitations of the underlying studies notwithstanding, some interim conclusions can be reached. For all but several forms of cancer, there is no suggestion that persons who have taken acetaminophen are at altered risk, even persons who have consumed a large quantity of the drug or those who have taken it for an extended duration. While in some studies the incidence of renal cell carcinoma has been observed to be increased among acetaminophen users, several other studies have failed to observe any such association; the reason for the discrepant findings is unclear. Some of the small number of studies that have presented data on the incidence of lymphoma, leukemia, and plasma cell disorders have found the risk to be modestly higher in users than nonusers of acetaminophen, but the results of other studies of these malignancies will be needed to gauge the possible role of publication bias as the basis for the positive results.

The Role of NSAIDs in Breast Cancer Prevention and Relapse: Current Evidence and Future Perspectives

Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) have received considerable interest as potential chemopreventive agents. The aim of this review is to summarize the accumulated knowledge on the effect of NSAIDs on breast cancer incidence and natural history, and the underlying pathophysiology. NSAIDs mainly block inflammation by inhibiting cyclooxygenase enzymes, leading to lower prostaglandin synthesis. The latter has been reported to affect breast cancer risk through hormonal and inflammation-related pathways. Intensity, dose, frequency, duration, and timing of administration may also be significant. There is currently enough evidence to support a role of NSAIDs in breast cancer prevention and relapse, which deserves further large-scale experimental and clinical investigation.

Lifetime use of nonsteroidal anti-inflammatory drugs and breast cancer risk: results from a prospective study of women with a sister with breast cancer

Background

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to inhibit several pathways in experimental models of breast carcinogenesis, but epidemiological evidence remains insufficient to support their use for breast cancer prevention. We examined the association between use of NSAIDs and breast cancer risk in a prospective cohort.

Methods

The Sister Study is a prospective cohort study of women who had a sister(s) with breast cancer. As of December 2013, 2118 incident breast cancers were ascertained from 50,884 women enrolled between 2003 and 2009. Lifetime history of NSAID use was estimated from self-reported data in pill-years, with 1 pill per week for a year equivalent to 1 pill-year. Cox regression models were used to estimate hazard ratios (HRs) of breast cancer in relation to pill-years of use for different NSAIDs, with adjustment for potential confounders.

Results

In the full cohort, although there was some evidence that use of non-aspirin, non-COXib NSAIDs was associated with lower breast cancer risk, there was little evidence of overall association for most categories of NSAID use. Among postmenopausal women NSAID use was not associated with reduced risk of breast cancer. However, among premenopausal women there was significantly reduced risk for any NSAID (HR_4vs1 = 0.66, 95 % CI: 0.50–0.87) and specifically for aspirin (HR_4vs1 = 0.57, 95 % CI: 0.33–0.98), with small, but non-significant reductions in risk for other drug classes.

Conclusion

Women with a sister with breast cancer are themselves at increased risk and might benefit the most from chemoprevention. Although there was little evidence of protective effect from NSAIDs in the overall cohort of women or among the subset who are postmenopausal, there is intriguing evidence that NSAID use, particularly aspirin, may reduce risk among premenopausal women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1979-1) contains supplementary material, which is available to authorized users.

Effect of COX-2 inhibitors and other non-steroidal inflammatory drugs on breast cancer risk: a meta-analysis

Evidence on non-steroidal anti-inflammatory drugs (NSAID) use and breast cancer risk shows a slightly protective effect of these drugs, but previous studies lack randomized clinical trial results and present high heterogeneity in exposure measurement. This systematic review and meta-analysis widens the knowledge about NSAID use and breast cancer risk, updating the information from the last meta-analysis, focusing on evidence on specific effects of COX-2 inhibitors and differential expression patterns of hormonal receptors. A PubMed-database search was conducted to include all entries published with the keywords "BREAST CANCER NSAID ANTI-INFLAMMATORY" until 10/24/2013 providing original results from cohort studies, case-control studies, or randomized clinical trials with at least one reported relative risk (RR) or odds ratio (OR) on the association between any NSAID use and incidence of invasive breast cancer. This resulted in 49 publications, from which the information was retrieved about type of study, exposure characteristics, breast cancer characteristics, and breast cancer-NSAID association. Meta-analyses were performed separately for case-control and cohort studies and for different hormone-receptor status. NSAID use reduced invasive breast cancer risk by about 20 %. A similar effect was found for aspirin, acetaminophen, COX-2 inhibitors and, to a lesser extent, ibuprofen. The effect of aspirin was similar in preventing hormone-receptor-positive breast cancer. This meta-analysis suggests a slightly protective effect of NSAIDs-especially aspirin and COX-2 inhibitors- against breast cancer, which seems to be restricted to ER/PR+tumors.

Cyclooxygenase-2 and the inflammogenesis of breast cancer

Cohesive scientific evidence from molecular, animal, and human investigations supports the hypothesis that constitutive overexpression of cyclooxygenase-2 (COX-2) is a ubiquitous driver of mammary carcinogenesis, and reciprocally, that COX-2 blockade has strong potential for breast cancer prevention and therapy. Key findings include the following: (1) COX-2 is constitutively expressed throughout breast cancer development and expression intensifies with stage at detection, cancer progression and metastasis; (2) essential features of mammary carcinogenesis (mutagenesis, mitogenesis, angiogenesis, reduced apoptosis, metastasis and immunosuppression) are linked to COX-2-driven prostaglandin E2 (PGE-2) biosynthesis; (3) upregulation of COX-2 and PGE-2 expression induces transcription of CYP-19 and aromatase-catalyzed estrogen biosynthesis which stimulates unbridled mitogenesis; (4) extrahepatic CYP-1B1 in mammary adipose tissue converts paracrine estrogen to carcinogenic quinones with mutagenic impact; and (5) agents that inhibit COX-2 reduce the risk of breast cancer in women without disease and reduce recurrence risk and mortality in women with breast cancer. Recent sharp increases in global breast cancer incidence and mortality are likely driven by chronic inflammation of mammary adipose and upregulation of COX-2 associated with the obesity pandemic. The totality of evidence clearly supports the supposition that mammary carcinogenesis often evolves as a progressive series of highly specific cellular and molecular changes in response to induction of constitutive over-expression of COX-2 and the prostaglandin cascade in the “inflammogenesis of breast cancer”.

Enalapril and ASS inhibit tumor growth in a transgenic mouse model of islet cell tumors

Accumulating evidence suggests a role for angiotensin-converting enzymes involving the angiotensin II-receptor 1 (AT1-R) and the cyclooxygenase pathway in carcinogenesis. The effects of ASS and enalapril were assessed in vitro and in a transgenic mouse model of pancreatic neuroendocrine neoplasms (pNENs). The effects of enalapril and ASS on proliferation and expression of the AGTR1A and its target gene vascular endothelial growth factor (Vegfa) were assessed in the neuroendocrine cell line BON1. Rip1-Tag2 mice were treated daily with either 0.6 mg/kg bodyweight of enalapril i.p., 20 mg/kg bodyweight of ASS i.p., or a vehicle in a prevention (weeks 5-12) and a survival group (week 5 till death). Tumor surface, weight of pancreatic glands, immunostaining for AT1-R and nuclear factor kappa beta (NFKB), and mice survival were analyzed. In addition, sections from human specimens of 20 insulinomas, ten gastrinomas, and 12 non-functional pNENs were evaluated for AT1-R and NFKB (NFKB1) expression and grouped according to the current WHO classification. Proliferation was significantly inhibited by enalapril and ASS in BON1 cells, with the combination being the most effective. Treatment with enalapril and ASS led to significant downregulation of known target genes Vegf and Rela at RNA level. Tumor growth was significantly inhibited by enalapril and ASS in the prevention group displayed by a reduction of tumor size (84%/67%) and number (30%/45%). Furthermore, daily treatment with enalapril and ASS prolonged the overall median survival compared with vehicle-treated Rip1-Tag2 (107 days) mice by 9 and 17 days (P=0.016 and P=0.013). The AT1-R and the inflammatory transcription factor NFKB were abolished completely upon enalapril and ASS treatment. AT1-R and NFKB expressions were observed in 80% of human pNENs. Enalapril and ASS may provide an approach for chemoprevention and treatment of pNENs.

Clinical evidence of the relationship between aspirin and breast cancer risk (review)

In the search for new therapeutic alternatives against cancer, either as a preventive treatment or for advanced stages, it is common to appeal to well-known drugs used for the treatment of other diseases that may interfere with the metabolic pathways involved in carcinogenesis. Non-steroidal anti-inflammatory drugs (NSAIDs) display anticancer activity through the inhibition of the COX-2 enzyme, triggering processes such as apoptosis, a reduction in proliferation and inhibition of carcinogenesis. Breast cancer is a neoplasm with the highest incidence and mortality rate among young women worldwide. Epidemiologic data have shown that drugs such as NSAIDs, particularly aspirin, reduce the relative risk of breast cancer. However, in the subgroup of responsive patients, dose, time and frequency of use have not yet been established. Here, we review the reports published during the last 10 years regarding the relationship between breast cancer and aspirin.

Initiation of aspirin therapy modulates angiogenic protein levels in women with breast cancer receiving tamoxifen therapy

Aspirin has a range of antineoplastic properties linked to inhibition of cyclooxygenase enzymes in tumor cells, platelet inhibition and to inhibition of angiogenesis. We undertook a prospective study to determine the influence of a 45-day course of aspirin therapy on circulating and intraplatelet levels of selected proangiogenic (vascular endothelial growth factor [VEGF]) and antiangiogenic (thrombospondin-1 [TSP-1]) proteins, and platelet protein release in women diagnosed with breast cancer who were receiving tamoxifen therapy. Initiation of aspirin therapy increases serum and intraplatelet levels of TSP-1 without a corresponding increase in VEGF levels. Following aspirin therapy, VEGF levels decreased (relative to pretreatment levels) while TSP-1 returned to pretreatment levels. Plasma TSP-1 and VEGF levels did not change on aspirin therapy. Aspirin use also decreased thrombin receptor mediated release of TSP-1 and VEGF from platelets. The selective impact on platelet angiogenic protein content and release supports one mechanism by which aspirin can modify the angiogenic balance in women receiving tamoxifen therapy. Aspirin therapy appears to favor an overall antiangiogenic balance in women with breast cancer who are receiving tamoxifen therapy.

Sex differences in effects and use of anti-inflammatory drugs

Gender accounts for important differences in the incidence, prevalence, and course of many immunoinflammatory diseases. However, similar treatment strategies, such as the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and tumor necrosis factor-α (TNF-α) inhibitors, have been advocated for both genders. Experimental studies found that molecular mechanisms of inflammation differ in males and females. In our chapter we summarize the data concerning gender-specific aspects about prevalence of use, drug survival, responsiveness, and adverse drug effects of NSAIDs and TNF-α inhibitors. Gender-related differences in the prevalence and course of many autoimmune diseases as well as differences in effects of anti-inflammatory drugs should be considered for the tailored treatment options for these patients.

Use of aspirin, other nonsteroidal anti-inflammatory drugs, and acetaminophen and postmenopausal breast cancer incidence

PURPOSE

The associations between use of aspirin, other nonsteroidal anti-inflammatory drugs (NSAIDs), and acetaminophen and breast cancer incidence in postmenopausal women are uncertain. We examined these associations with breast cancer, both overall and by molecular subtype.

PATIENTS AND METHODS

We observed 84,602 postmenopausal women, free of cancer in 1980, until June 2008 and prospectively collected data on analgesic use, reproductive history, and other lifestyle factors using biennial questionnaires. Proportional hazards models were used to estimate multivariable relative risks (RRs) and 95% CIs.

RESULTS

We documented 4,734 cases of incident invasive breast cancer. Compared with nonuse of aspirin, multivariable RRs of regular aspirin use (≥ two tablets per week) for more than 20 years were 0.91 for overall breast cancer (95% CI, 0.81 to 1.01; P(trend) = 0.16), 0.90 for estrogen receptor (ER) -positive progesterone receptor (PR) -positive breast cancer (95% CI, 0.77 to 1.06; P(trend) = 0.17), and 0.91 for ER-negative PR-negative breast cancer (95% CI, 0.68 to 1.22; P(trend) = 0.97). Results did not vary appreciably by past or current use, days per week of use, or dosage of use. Use of other NSAIDs and acetaminophen was largely not significantly associated with breast cancer risk. Additionally, use of higher doses of each analgesic (≥ six tablets per week) for more than 10 years was generally not significantly associated with risk of breast cancer, either overall or by subtype. Furthermore, largely no substantial associations were noted for breast cancer molecular subtypes, including luminal A, luminal B, triple negative, basal-like, human epidermal growth factor receptor 2 positive, cyclooxygenase-2 (COX-2) negative, and COX-2 positive.

CONCLUSION

Our study suggests that use of aspirin, other NSAIDs, and acetaminophen is not importantly associated with risk of postmenopausal breast cancer, either overall or by specific subtype.

Aspirin and cancer risk: a quantitative review to 2011

BACKGROUND

Aspirin has been associated to a reduced risk of colorectal and possibly of a few other common cancers.

METHODS

To provide an up-to-date quantification of this association, we conducted a meta-analysis of all observational studies on aspirin and 12 selected cancer sites published up to September 2011.

RESULTS

Regular aspirin is associated with a statistically significant reduced risk of colorectal cancer [summary relative risk (RR) from random effects models = 0.73, 95% confidence interval (CI) 0.67-0.79], and of other digestive tract cancers (RR = 0.61, 95% CI = 0.50-0.76, for squamous cell esophageal cancer; RR = 0.64, 95% CI = 0.52-0.78, for esophageal and gastric cardia adenocarcinoma; and RR = 0.67, 95% CI = 0.54-0.83, for gastric cancer), with somewhat stronger reductions in risk in case-control than in cohort studies. Modest inverse associations were also observed for breast (RR = 0.90, 95% CI = 0.85-0.95) and prostate cancer (RR = 0.90, 95% CI = 0.85-0.96), while lung cancer was significantly reduced in case-control studies (0.73, 95% CI = 0.55-0.98) but not in cohort ones (RR = 0.98, 95% CI = 0.92-1.05). No meaningful overall associations were observed for cancers of the pancreas, endometrium, ovary, bladder, and kidney.

CONCLUSIONS

Observational studies indicate a beneficial role of aspirin on colorectal and other digestive tract cancers; modest risk reductions were also observed for breast and prostate cancer. Results are, however, heterogeneous across studies and dose-risk and duration-risk relationships are still unclear.

Aspirin use and breast cancer risk: a meta-analysis

Animal and in vitro studies suggest that the use of aspirin may be associated with reduced risk for breast cancer, but results from these studies of the association have been inconsistent. The objective of this meta-analysis was to quantitatively summarize the current evidence for such a relationship. We searched MEDLINE for studies of aspirin use and breast cancer risk that were published in any language, from January 1, 1966, to July 1, 2011. A total of 33 studies (19 cohort studies, 13 case-control studies, and 1 randomized controlled trial [RCT]) that included 1,916,448 subjects were identified. We pooled the relative risks from individual studies using a random-effects model, heterogeneity, and publication bias analyses. In a pooled analysis of all studies, aspirin use was associated with reduced risk for breast cancer (odds ratio [OR] = 0.86, 95% confidence interval [CI] = 0.81, 0.92). In the subgroup analysis by study design, results were similar except for RCT (OR = 0.98, 95% CI = 0.87, 1.09). In conclusion, this meta-analysis indicated that regular use of aspirin may be associated with reduced risk of breast cancer. More RCT were needed to confirm this association in the future.

Hormonal mechanisms underlying the relationship between obesity and breast cancer

Given the worldwide epidemic of obesity, it is inevitably an increasingly common comorbidity for women who develop breast cancer; therefore, it is critical to understand its impact on this disease. This review focuses on the influence of obesity on breast cancer development and progression and describes the hormonal factors that may underlie the observations, with particular emphasis on the roles of estrogen, insulin/insulin-like growth factor axis, and adipokines.

Regular aspirin use and breast cancer risk in US Black women

BACKGROUND

Epidemiologic studies have yet to provide consistent evidence to support a protective effect of aspirin and other non-steroidal anti-inflammatory drugs (NSAID) on the incidence of breast cancer.

OBJECTIVE

We evaluated the relations of current use of aspirin, non-aspirin NSAIDs, and acetaminophen with breast cancer incidence in the Black Women's Health Study.

METHODS

Biennial follow-up of 59,000 study participants began in 1995. During 558,600 person-years of follow-up through 2007, 1,275 breast cancer cases were identified. Using Cox proportional hazards regression, we estimated incidence rate ratios (IRR) and 95% confidence intervals (CI) for associations of current and former use of aspirin, other NSAIDs, and acetaminophen with incident breast cancer.

RESULTS

After adjustment for age, education, body mass index at age 18, physical activity, female hormone use, current smoking, and other NSAID use, the IRRs were 0.79 (95% CI = 0.66, 0.95) for current aspirin use and 0.68 (95% CI = 0.50, 0.92) for ≥5 years of aspirin use. Similar associations were observed for acetaminophen use.

CONCLUSIONS

Both aspirin and acetaminophen use were inversely associated with breast cancer incidence in the present study. Reasons for the association with acetaminophen use are unclear, given that acetaminophen has very weak anti-inflammatory effects.

Effect of cyclooxygenase inhibitors in a xenograft model of canine mammary tumours

Inhibition of cyclooxygenase-2 (COX-2) represents a possible avenue for the prevention and/or treatment of some cancers. Our goal was to compare the effect of a selective inhibitor of COX-2, deracoxib, and a COX-1 and -2 inhibitor, piroxicam, on the growth of canine mammary tumours in a murine model. CMT-9 was used to induce xenografts in nude mice. Mice were treated with piroxicam (0.6 mg kg(-1)), deracoxib (6 mg kg(-1)) or a control solution. Tumour volumes between 0 and 24 days post-treatment showed no significant difference between all groups. A second series of experiments was performed with a higher dose of piroxicam (0.9 mg kg(-1)). Tumour volumes between 14 and 21 days post-treatment were significantly smaller in piroxicam-treated mice compared with controls. These results demonstrate that COX inhibition reduced the growth of canine mammary cancer xenografts in mice, suggesting that COX inhibitors could have a positive effect in dogs.

Non-steroidal anti-inflammatory drug (NSAID) use and breast cancer risk in the Western New York Exposures and Breast Cancer (WEB) Study

OBJECTIVE

Chronic inflammation is suspected to have a role in breast carcinogenesis. Results of studies of non-steroidal anti-inflammatory drugs (NSAIDs) and breast cancer have been inconsistent. Timing of exposure and analysis of individual NSAIDs should be considered.

METHODS

We conducted a population-based case-control study in western New York State between 1996 and 2001. Cases, 35-79 years, had incident, primary, histologically confirmed breast cancer (n = 1,170). Controls (n = 2,115) were randomly selected from NY Department of Motor Vehicles records (<65 years) or Medicare rolls (>or=65 years). Participants were queried on use of aspirin, ibuprofen, and acetaminophen in the year prior and on aspirin during adulthood. Unconditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Recent aspirin use was inversely associated with breast cancer risk (adjusted OR 0.80, 95% CI: 0.68-0.94); the strongest reduction in risk was observed among those who took >or=2 pills/day on days that aspirin was taken (OR 0.74, 95% CI: 0.61-0. 90). Adult lifetime use was also associated with breast cancer risk (>10 days/month, adjusted OR 0.68, 95% CI: 0.46-1.00). Use of ibuprofen or acetaminophen was not associated with breast cancer.

CONCLUSIONS

This is the first study to investigate the association of adult lifetime aspirin intake with breast cancer risk. Our findings provide evidence that aspirin use throughout a woman's life may confer some benefit.

Low-dose aspirin in the primary prevention of rheumatoid arthritis: the Women's Health Study

OBJECTIVE

Low-dose aspirin may reduce the risk of developing rheumatoid arthritis (RA) through its effect on cyclooxygenase activity and its antioxidant pathways. Previous randomized trial data have demonstrated a beneficial effect of low-dose aspirin in reducing other inflammatory diseases, such as asthma and colorectal adenomas, but no trial has evaluated the role of aspirin in RA prevention.

METHODS

The Women's Health Study is a randomized, double-blind, placebo-controlled trial conducted between 1992 and 2004 designed to evaluate the risks and benefits of low-dose aspirin (100 mg every other day) and vitamin E in the primary prevention of cardiovascular disease and cancer among 39,876 female health care professionals age > or =45 years throughout the US. After excluding women with RA at baseline, 39,144 women were evaluated for the present study. A definite diagnosis of RA was assessed during followup by self-report and confirmed using a connective tissue disease screening questionnaire, followed by a medical record review by a rheumatologist for American College of Rheumatology criteria.

RESULTS

During an average followup of 10 years, 106 women developed definite RA (48 women in the aspirin group and 58 in the placebo group). There was a nonsignificant risk for RA (relative risk [RR] 0.83, 95% confidence interval [95% CI] 0.56-1.21; P = 0.33) associated with aspirin. There were 64 seropositive RA cases (60%) and 42 seronegative RA cases (40%). Aspirin also had no significant effect on either seropositive RA (RR 1.0, 95% CI 0.61-1.63) or seronegative RA (RR 0.62, 95% CI 0.33-1.15).

CONCLUSION

One hundred milligrams of aspirin taken every other day was not associated with a significant reduction in the risk of developing RA among women in a randomized, double-blind, placebo-controlled trial.

Prescriptions for selective cyclooxygenase-2 inhibitors, non-selective non-steroidal anti-inflammatory drugs, and risk of breast cancer in a population-based case-control study

INTRODUCTION

Non-steroidal anti-inflammatory drugs (NSAIDs) prevent the growth of mammary tumours in animal models. Two population-based case-control studies suggest a reduced risk of breast cancer associated with selective cyclooxygenase-2 (sCox-2) inhibitor use, but data regarding the association between breast cancer occurrence and use of non-selective NSAIDs are conflicting.

METHODS

We conducted a population-based case-control study using Danish healthcare databases to examine if use of NSAIDs, including sCox-2 inhibitors, was associated with a reduced risk of breast cancer. We included 8,195 incident breast cancer cases diagnosed in 1991 through 2006 and 81,950 population controls.

RESULTS

Overall, we found no reduced breast cancer risk in ever users (>2 prescriptions) of sCox-2 inhibitors (odds ratio (OR) = 1.08, 95% confidence interval (95% CI) = 0.99, 1.18), aspirin (OR = 0.98, 95% CI = 0.90-1.07), or non-selective NSAIDs OR = 1.04, (95% CI = 0.98, 1.10)). Recent use (>2 prescriptions within two years of index date) of sCox-2 inhibitors, aspirin, or non-selective NSAIDs was likewise not associated with breast cancer risk (Ors = 1.06 (95% CI = 0.96, 1.18), 0.96 (95% CI = 0.87, 1.06) and 0.99 (95% CI = 0.85, 1.16), respectively). Risk estimates by duration (<10, 10 to 15, 15+ years) or intensity (low/medium/high) of NSAID use were also close to unity. Regardless of intensity, shorter or long-term NSAID use was not significantly associated with breast cancer risk.

CONCLUSIONS

Overall, we found no compelling evidence of a reduced risk of breast cancer associated with use of sCox-2 inhibitors, aspirin, or non-selective NSAIDs.

Adipose tissue as target organ in the treatment of hormone-dependent breast cancer: new therapeutic perspectives

Breast cancer is the female malignant neoplasia with the highest incidence in the industrialized world. Despite many undeniable therapeutic successes obtained, breast cancer still remains, however, a major health issue. In the last few years, thanks to aromatase inhibitors, the hormone therapy for oestrogen-dependent breast cancer has evolved in terms of efficacy and tolerability; at the same time, it has enabled us to better define the role of oestrogens in the etiopathogenesis of this tumour. Weight increase and obesity have been identified as the most important risk and prognostic factors for breast cancer in postmenopausal women. Several hypotheses have been proposed to explain the association of obesity with postmenopausal breast cancer. A more recent hypothesis suggests that adipocytes and their autocrine (paracrine and endocrine actions) are at the centre of such an etiopathogenetic mechanism. A better understanding of the main mechanisms that link together menopause, body-weight increase and hormone-dependent breast cancer is paramount to enable the identification of key molecules involved in the development of breast carcinoma and suggest new therapeutic options. The present review will discuss important findings on the therapeutic aspects of adipose tissue and adipokines as a target for treatment of hormone-dependent breast cancer.

Use of aspirin, other nonsteroidal anti-inflammatory drugs, and acetaminophen and risk of breast cancer among premenopausal women in the Nurses' Health Study II

BACKGROUND

The use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) is widespread for treatment of common symptoms such as headaches, muscular pain, and inflammation. In addition, the chemopreventive use of NSAIDs is increasingly common for heart disease and colon cancer. Evidence of a protective association with breast cancer risk has been inconsistent, and few data exist for premenopausal women.

METHODS

We assessed the associations for use of aspirin, other NSAIDs, and acetaminophen with breast cancer risk among premenopausal women in the prospective Nurses' Health Study II. In total, 112,292 women, aged 25 to 42 years and free of cancer in 1989, were followed up until June 2003. Multivariate relative risks and 95% confidence intervals were calculated by Cox proportional hazards models, adjusting for age and other important breast cancer risk factors.

RESULTS

Overall, 1345 cases of invasive premenopausal breast cancer were documented. Regular use of aspirin (> or = 2 times per week) was not significantly associated with breast cancer risk (relative risk, 1.07; 95% confidence interval, 0.89-1.29). Regular use of either nonaspirin NSAIDs or acetaminophen also was not consistently associated with breast cancer risk. Results did not vary by frequency (days per week), dose (tablets per week), or duration of use. Furthermore, associations with each drug category did not vary substantially by estrogen and progesterone receptor status of the tumor.

CONCLUSION

These data suggest that the use of aspirin, other NSAIDs, and acetaminophen is not associated with a reduced risk of breast cancer among premenopausal women.

Aspirin and cancer risk: a summary review to 2007

Aspirin has been associated with a reduced risk of colorectal cancer and--based on limited evidence--to cancers of the oesophagus, stomach, breast, ovary and lung. The role of aspirin on other cancers, such as pancreatic, prostate and bladder cancer and non-Hodgkin's lymphomas and myeloma is less clear, and an increase of risk has been suggested for kidney cancer. For most cancer sites, however, significant heterogeneity between studies, and particularly between study design, was found, with a reduction in risk generally stronger in case-control studies than in cohort ones.

Use of common medications and breast cancer risk

Prescription and over-the-counter medications are widely used in the United States and many western countries. More than two-thirds of women ages >45 years, who are at greatest risk for breast cancer, take prescription medication. In light of the ubiquitous nature of medication use and the fact that breast cancer remains the most common cancer in women, research on the role of medication use in breast cancer etiology is warranted. We summarize the epidemiologic evidence on the association between breast cancer risk and use of common medications, including antibiotics, antidepressants, statins, antihypertensives, and nonsteroidal anti-inflammatory drugs. Overall, there is little evidence that would implicate the use of antibiotics, antidepressants, statins, and antihypertensives in the etiology of breast cancer. Although several prospective studies and a randomized low-dose aspirin chemoprevention trial have not shown lower risk of breast cancer among aspirin users, most studies that have examined the potential chemoprotective effect of nonsteroidal anti-inflammatory drugs have shown significant risk reductions for regular and prolonged use of these drugs. The existing literature on the role of medication use in breast carcinogenesis is complicated. Interpretation of the evidence is hampered due to major methodologic differences across studies, including exposure assessment, exposure classification, and adjustment for potential confounding variables. These differences largely stem from the fact that the majority of articles on this topic represent secondary data analyses from studies with inadequate information on exposure or confounders. Thus, future epidemiologic studies specifically designed to study these ubiquitous and biologically plausible exposures are warranted.

Association between NSAIDs use and breast cancer risk: a systematic review and meta-analysis

The association between non-steroidal anti-inflammatory drugs (NSAIDs) use and breast cancer has remained controversial. Therefore, an overall quantitative estimate of the association needs to be studied. A systematic review and meta-analysis was executed to explore the pooled estimate for relative risk (RR) and 95% confidence interval (CI) using random or fixed effects models based on heterogeneity analysis. Overall 26 studies with 528,705 participants were included. The RR of NSAIDs use and the incidence of breast cancer was 0.94 (95% CI: 0.88-1.00) with random effects model. A slight reduction of breast cancer by taking aspirin and ibuprofen was both observed with pooled RR of 0.91 (95% CI: 0.83-0.98) and 0.81 (95% CI: 0.67-0.97), respectively. Our results indicate that NSAIDs use is associated with a slight decrease for the development of breast cancer with a marginally statistical significant difference. The associations are slightly more obvious in aspirin and ibuprofen use.

Breast cancer and use of nonsteroidal anti-inflammatory drugs: a meta-analysis

BACKGROUND

Breast cancer is one of the leading causes of mortality among women. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) may be associated with reduced risk for breast cancer, but results from these studies of the association have been inconsistent.

METHODS

Studies that examined the association between risk of breast cancer and use of NSAIDs, including aspirin and ibuprofen, that were published between January 1, 1966, and July 1, 2008, were identified using Medline, EMBASE, and other databases. We performed meta-analysis by pooling studies according to the inverse of their variances and performed separate analyses of studies pooled according to aspirin use and ibuprofen use. We evaluated publication bias and study quality.

RESULTS

A total of 38 studies (16 case-control studies, 18 cohort studies, 3 case-control studies nested in well-defined cohorts, and 1 clinical trial) that included 2 788 715 subjects were identified. The results of these studies suggest that overall, NSAID use was associated with reduced risk for breast cancer (relative risk [RR] = 0.88, 95% confidence interval [CI] = 0.84 to 0.93). Specific analyses for aspirin (RR = 0.87, 95% CI = 0.82 to 0.92) and ibuprofen (RR = 0.79, 95% CI = 0.64 to 0.97) yielded similar results.

CONCLUSIONS

This meta-analysis provides evidence that NSAID use is associated with reduced risk for breast cancer. Future research should include careful evaluation of the biologic mechanisms involved in the relationship between NSAIDs and breast cancer.

Nonsteroidal anti-inflammatory drugs and change in mammographic density: a cohort study using pharmacy records on over 29,000 postmenopausal women

BACKGROUND

Use of nonsteroidal anti-inflammatory drugs (NSAID) has been associated with a decrease in breast cancer risk, but it is unknown if they also reduce mammographic density, a strong intermediate marker of breast cancer risk.

METHODS

We investigated NSAID use and mammographic density in 29,284 postmenopausal women who had two screening mammograms at Group Health in Seattle. We used pharmacy records to classify women as NSAID nonusers, continuers, initiators, or discontinuers based on use between the two mammograms and nine separate prescription and nonprescription NSAID classes. Using unordered polytomous logistic regression methods, we modeled the odds ratio (OR) of staying not dense, decreasing density, or increasing density relative to remaining dense based on Breast Imaging Reporting Data System classification of density.

RESULTS

There was no association with density change from initiation or continuation of NSAIDs. However, both initiators and continuers of any NSAIDs were more likely to stay not dense than stay dense [OR, 1.12; 95% confidence interval (95% CI), 1.04-1.20; OR, 1.25; 95% CI, 1.05-1.49, respectively]. This association with staying not dense for initiators and continuers of any NSAID use was observed primarily among women ages <65 years at first mammogram (OR, 1.24; 95% CI, 1.12-1.36; OR, 1.48; 95% CI, 1.14-1.93, respectively).

CONCLUSIONS

Initiation of NSAID use did not reduce mammographic density over the short term. Continuers of NSAID use were more likely to stay not dense compared with nonusers, suggesting that it is plausible that longer-term use of NSAIDs may be needed to reduce density.

Nonsteroidal anti-inflammatory drug use and breast cancer risk: a Danish cohort study

Epidemiologic studies investigating the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on breast cancer have yielded conflicting results. We examined the association between use of aspirin and nonaspirin NSAIDs and breast cancer risk among 28 695 women in the Danish Diet, Cancer and Health cohort. Information on NSAID and paracetamol use was obtained from a self-administered questionnaire completed at baseline (1993-1997) and updated through 2003 using a nationwide prescription database. Detailed information on breast cancer incidence and tumour characteristics was obtained from nationwide health registers. Cox proportional hazards regression was used to compute incidence rate ratios (RRs) and 95% confidence intervals (CIs). We identified 847 breast cancer cases over an average follow-up period of 7.5 years. Any NSAID use at baseline was associated with an increased incidence of breast cancer compared with nonuse (RR, 1.27; 95% CI, 1.10-1.45). A similar result was observed for any NSAID use in a combined analysis of baseline and prescription data (1.34; 95% CI, 1.15-1.56). Aspirin-only users experienced a slightly higher breast cancer incidence (RR, 1.38; 95% CI, 1.12-1.69) than exclusive users of nonaspirin NSAIDs (RR, 1.25; 95% CI, 1.04-1.49). Introduction of a lag time of 1 year provided similar results. We found no clear differences in risk estimates with frequency, recency or duration of NSAID use, or by hormone receptor status of the breast tumours. Paracetamol use was unrelated to breast cancer incidence. The increased breast cancer incidence among NSAID users may reflect a noncausal association, but our study provides no evidence of a chemopreventive effect of NSAIDs against breast cancer over the durations studied.

Nonsteroidal anti-inflammatory drugs and breast cancer risk in the National Institutes of Health-AARP Diet and Health Study

Introduction

By inhibiting cyclooxygenase-2, nonsteroidal anti-inflammatory drugs (NSAIDs) decrease aromatase activity and might reduce breast cancer risk by suppressing estrogen synthesis. Epidemiologic evidence for a protective role of NSAIDs in breast cancer, however, is equivocal.

Methods

We tested NSAID use for its association with breast cancer incidence in the National Institutes of Health–AARP Diet and Health Study, where 127,383 female AARP (formerly known as the American Association of Retired Persons) members with no history of cancer, aged 51 to 72 years, completed a mailed questionnaire (1996 to 1997). We estimated relative risks of breast cancer for NSAID exposures using multivariate Cox proportional hazards regression models. The state cancer registry and mortality index linkage identified 4,501 primary incident breast cancers through 31 December 2003, including 1,439 estrogen receptor (ER)-positive cancers and 280 ER-negative cancers.

Results

Proportional hazards models revealed no statistically significant association between overall NSAIDs and total breast cancer. As cyclooxygenase inhibition by aspirin (but not other NSAIDs) is irreversible, we tested associations by NSAID type. Although we observed no significant differences in risk for daily use (versus nonuse) of aspirin (relative risk = 0.93, 95% confidence interval = 0.85 to 1.01) or nonaspirin NSAIDS (relative risk = 0.96, 95% confidence interval = 0.87 to 1.05), risk of ER-positive breast cancer was significantly reduced with daily aspirin use (relative risk = 0.84, 95% confidence interval = 0.71 to 0.98) – a relationship not observed for nonaspirin NSAIDS. Neither aspirin nor nonaspirin NSAIDs were associated with risk of ER-negative breast cancer.

Conclusion

Breast cancer risk was not significantly associated with NSAID use, but daily aspirin use was associated with a modest reduction in ER-positive breast cancer. Our results provide support for further evaluating relationships by NSAID type and breast cancer subtype.

Aspirin, NSAID, and acetaminophen use and the risk of endometrial cancer

To date, no prospective studies have explored the relationship between the use of aspirin, other nonsteroidal anti-inflammatory medications (NSAID), and acetaminophen and endometrial adenocarcinoma. Of the 82,971 women enrolled in a prospective cohort study, 747 developed medical record-confirmed invasive endometrial cancer over a 24-year period. Use of aspirin was ascertained from 1980 to 2004, and for other NSAIDs and acetaminophen, from 1990 to 2004. Cox regression models calculated multivariate relative risks (MV RR), controlling for body mass index (BMI), postmenopausal hormone (PMH) use, and other endometrial cancer risk factors. Currency, duration, and quantity of aspirin were not associated with endometrial cancer risk overall [current use: MV RR, 1.03; 95% confidence interval (CI) 0.83-1.27; >10 years of use: MV RR, 1.01; 95% CI, 0.78-1.30; and cumulative average >7 tablets per week: (MV RR, 1.10; 95% CI, 0.84-1.44)]. However, stratified analyses showed that a lower risk of endometrial cancer among obese (BMI, >or=30 kg/m(2)) women was seen with current aspirin use (MV RR, 0.66; 95% CI, 0.46-0.95). The greatest risk reduction for current aspirin users was seen in postmenopausal obese women who had never used PMH (MV RR, 0.43; 95% CI, 0.26-0.73). The use of other NSAIDs or acetaminophen was not associated with endometrial cancer. Our data suggest that use of aspirin or other NSAIDs does not play an important role in endometrial cancer risk overall. However, risk was significantly lower for current aspirin users who were obese or who were postmenopausal and had never used PMHs; these subgroup findings require further confirmation.

Low-dose aspirin and breast cancer risk: results by tumour characteristics from a randomised trial

The Women's Health Study trial previously reported no overall effect of low-dose aspirin (100 mg every other day) on invasive breast cancer over an average of 10 years of treatment. The present subgroup analyses further show no effects by tumour characteristics at diagnosis, suggesting that low-dose aspirin has no preventive effect on breast cancer.

NSAIDs and breast cancer: a possible prevention and treatment strategy

CONTEXT

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) and thereby reduce prostaglandin synthesis. Abnormally upregulated COX and prostaglandins are features of breast cancer so NSAIDs might have a role in treatment and prevention of the disease.

OBJECTIVE

To review the available epidemiological data on the relation between NSAIDs and risk of breast cancer together with interventional studies in established disease.

RESULTS

Both case-control and cohort studies indicate a moderate reduction in risk of breast cancer among women taking NSAID particularly aspirin. There may be a reduction in oestrogen receptor positive tumours in aspirin users but results are heterogeneous. It is not possible to estimate the dose-response effect for duration of use. In patients with breast cancer, aspirin increased levels of serum nitric oxide (NO) and maspin both of which inhibit growth of breast cancer cells in vitro. Furthermore, a reduced breast cancer and all-cause mortality has been reported in those taking NSAIDs after diagnosis. The cyclooxygenase 2 (COX-2) inhibitor celecoxib showed promising preliminary efficacy and acceptability in combination with exemestane in advanced breast cancer although cardiotoxicity led to discontinuation of celecoxib in a prevention trial for individuals with colonic polyps.

CONCLUSIONS

NSAIDs may reduce breast cancer risk by 20% but the optimal type, dose and duration is still undetermined together with the feasibility of such an intervention in an at risk population. There may be a role for NSAIDs in combination with endocrine therapies as either an adjuvant or palliative treatment for women with established breast cancer.

IL6, aspirin, nonsteroidal anti-inflammatory drugs, and breast cancer risk in women living in the southwestern United States

Interleukin-6 is a cytokine thought to be involved in inflammation, insulin, and estrogen-related pathways. We evaluate genetic variation in the IL6 gene with risk of breast cancer. We also evaluate breast cancer associations with aspirin and nonsteroidal anti-inflammatory drugs. A breast cancer case-control study (n = 1,527 non-Hispanic white cases, 1,601 non-Hispanic white controls, 798 Hispanic/Native American cases, and 924 Hispanic/Native American controls) was conducted among women living in the southwestern United States (4-Corner's Breast Cancer Study). Five IL6 single nucleotide polymorphisms (SNP) and IL6 haplotypes based on these SNPs were evaluated. Allele frequencies were significantly different between non-Hispanic white and Hispanic/Native American women. Among postmenopausal women not recently exposed to hormones, the AG/GG genotypes of rs1800797 (-596A>G) and the GC/CC genotypes of rs1800795 (-174G>C) significantly reduced risk of breast cancer among non-Hispanic white women [odds ratio (OR), 0.69; 95% confidence interval (95% CI), 0.48-1.00 and OR, 0.68; 95% CI, 0.47-0.99, respectively] and Hispanic/Native American women (OR, 0.48; 95% CI, 0.28-0.83 and OR, 0.44; 95% CI, 0.26-0.99, respectively). Haplotypes of the five IL6 SNPs further defined these associations. Recent aspirin use significantly decreased risk of breast cancer among postmenopausal Hispanic/Native American women not recently exposed to hormones (OR, 0.56; 95% CI, 0.33-0.96). Among non-Hispanic white, the inverse association with aspirin was not statistically significant. IL6 genotype and haplotype significantly modified the association between aspirin and breast cancer, with the greatest effect modification being among women not recently exposed to hormones [P interaction = 0.06 (for non-Hispanic white) and 0.04 (for Hispanic/Native American) and SNP rs1800796 or -572G>C]. These data suggest that IL6 is associated with breast cancer risk and modifies the association between estrogen and aspirin and breast cancer risk.

C-Reactive Protein and Risk of Breast Cancer

Chronic inflammation is hypothesized to be associated with breast cancer development. However, data evaluating the association between C-reactive protein (CRP), a marker of systemic inflammation, and breast cancer risk are sparse. In the Women's Health Study, 27,919 apparently healthy women aged 45 years and older who were free of cancer and cardiovascular disease had plasma CRP levels measured at baseline. During a mean of 10 years of follow-up, a total of 892 women developed invasive breast cancer. All statistical tests were two-sided. Baseline plasma CRP level was not statistically significantly associated with breast cancer risk (highest versus lowest quintile of CRP, multivariable hazard ratio = 0.90, 95% confidence interval = 0.71 to 1.16; P(trend) = .19; crude incidence rates: 273 versus 305 per 100,000 person-years). Our data suggest that baseline plasma CRP levels are not associated with the increased risk of breast cancer in apparently healthy women.